This invention is in the field concerning pneumatic tube systems for forwarding transporter capsules. More specifically, the invention relates to accomplishing a swerve (change in pitch) in the direction of travel of the transporter capsule at bends in the pneumatic forwarding tube systems.
Hitherto, in pneumatic forwarding tube systems for forwarding of transporter capsules, a desired swerve in the direction of longitudinal travel of a transporter capsule, the swerve (change in pitch) being an angular displacement of 90 degrees or any other functionally necessary angular displacement in the travel, is effected by means of the capsule performing a curvilinear motion while the capsule transits through an arcuate bend in the tube, the bend being coincident with the desired swerve. This bend cannot be in the shape of a sharp turn, but curvature of the bend has necessarily to be in the shape of a gradual arc, with a radius of curvature of the arc being adequately large to allow the straight length of dimension of the capsule and diametrical dimension of the capsule to pass curvilinearly through the bend in the tube.
This large radius of the bend occupies a relatively large physical area. The area required is often not easily available at the site of installation of the system. Often space is also expensive at the site. Therefore the physical area required for achieving the swerve should be minimal.
In some conventional systems, a lateral cylindrical recess is necessary at the middle of midriff region of the capsule so as to accommodate the convex inside tube surface at the bend. With this construction, convexity of the inside tube surface protrudes into the recess when the capsule traverses the bend.
The recess constricts the transverse cross-sectional diametrical dimension of the capsule at the midriff region. As cargo carried inside the capsule is constrained to the internal diameter of the capsule at the constricted midriff, the recess reduces the volumetric cargo transporting capacity of the capsule. A uniform cylinder shaped cargo cannot have a diameter greater than the minimum internal diameter at the midriff, whereby cylinder capacity of the capsule is defined by the diameter and length of a uniform cylinder than can be contained inside the capsule.
The cross-sectional internal diameter of the tube forwarding the capsule then matches the outermost diameter of the capsule, which is appreciably larger than cross-sectional internal diameter at the constricted midriff of the capsule. It is easy to see that expensive space inside the tube is not well utilized for transporting cargo, the cargo being constrained to the constricted midriff. For example, in existing systems a forwarding tube of 90 mm cross-sectional internal diameter can carry a cylinder shaped cargo of 60 mm diameter only.
In conventional tube forwarding systems, straight length overall dimension of the capsule has to be limited so as to allow the capsule to dimensionally pass through the bend in the tube, thereby limiting volumetric cargo transporting capacity of the system. For example, hitherto a tube internal cross-sectional diameter of 90 mm and a bend of as large as 750 mm radius can forward a capsule of only 320 mm length.
In coventional systems, particular cylinder capacities of the capsule can be transported if the system has a minimum diameter of the tube and a minimum radius at the bend as stated in Table 1, in mm.
TABLE 1 ______________________________________ Cylinder Capacity of Capsule: Diameter .times. Length Tube Diameter Bend Radius ______________________________________ 63 550 60 .times. 245 650 60 .times. 320 750 80 .times. 245 650 90 .times. 415 1000 ______________________________________
The device according to the present invention obviates the above disadvantages and also provides new and desirable features.